Xiaojun Tang

Mesenchymal stem cells promote CD206 expression and phagocytic activity of macrophages through IL-6 in systemic lupus erythematosus.

Human umbilical cord-derived mesenchymal stem cells (UCMSCs) show therapeutic effects on systemic lupus erythematosus (SLE). Deficiency in functional polarization and phagocytosis in macrophages has been suggested in the pathogenesis of SLE. We found that macrophages from B6.MRL-Fas(lpr) mice exhibited lower level of CD206, the marker for alternatively activated macrophage (AAM, also called M2). In addition, the phagocytic activity of B6.MRL-Fas(lpr) macrophages was also decreased. UCMSC transplantation improved the proportion of CD206(+) macrophages and their phagocytic activity in B6.MRL-Fas(lpr) mice. Importantly, macrophages from SLE patients also showed lower expression of CD206 and reduced phagocytic activity, which were corrected by being co-cultured with UCMSCs in vitro and in SLE patients receiving UCMSC transplantation. Mechanistically, we demonstrated that IL-6 was required for the up-regulation of CD206 expression and phagocytic activity of UCMSC-treated SLE macrophages. Our results indicate that UCMSCs alleviate SLE through promoting CD206 expression and phagocytic activity of macrophages in an IL-6 dependent manner.

Exacerbation of lupus nephritis by high sodium chloride related to activation of SGK1 pathway

The objective of this study is to explore the effects of high salt diet (HSD) on the severity of lupus nephritis (LN) and its mechanism. MRL/lpr mice were randomly divided into two groups, which were fed with normal diet or sodium-rich chow and tap. C57BL/6 mice were selected as control. Spleen Th1, Th2, Th17 and Treg cells were detected by flow cytometry. Serum TGF-β and IL-17 were measured by enzyme-linked immunosorbent assay. CD4(+) T cells from Systemic Lupus Erythematosus (SLE) patients and healthy donors were treated by NaCl with or without SGK1 inhibitor. Then, Th17 and Treg cells were detected. The HSD MRL/lpr mice had decreased survival rate and increased disease severity. The frequencies of Th1 and Th17 cells increased in HSD treatment group. The ratios of Th1/Th2 and Th17/Treg in HSD treated MRL/lpr mice significantly increased. Serum TGF-β increased after HSD treatment. In vitro, high salt could up-regulate Th17 cells of CD4(+) T cells. The effects of high salt treatment on CD4(+) T cells were reversed by SGK1 inhibitor. Our findings demonstrated that excessive intake of salt in diet is an aggravating factor for LN. High salt diet may deteriorate LN through SGK1 pathway.

Human Umbilical Cord Mesenchymal Stem Cells Inhibit T Follicular Helper Cell Expansion through the Activation of iNOS in Lupus-Prone B6.MRL-Faslpr Mice

The aberrant generation or activation of T follicular helper (Tfh) cells contributes to the pathogenesis of systemic lupus erythematosus (SLE), yet little is known about how these cells are regulated. In this study, we demonstrated that the frequency of Tfh cells was increased in lupus-prone B6.MRL-Faslpr (B6.lpr) mice and positively correlated to plasma cell proportions and serum total IgG as well as anti-dsDNA antibody levels. Transplantation of mesenchymal stem cells derived from Whartons jelly of human umbilical cords (hUC-MSCs) ameliorated lupus symptoms in B6.lpr mice, along with decreased percentages of Tfh cells. In vitro studies showed that the differentiation and proliferation of Tfh cells were markedly suppressed by hUC-MSCs. The production of inducible nitric oxide synthase (iNOS) was dramatically upregulated in hUC-MSCs when cocultured with CD4+ T cells directly, while adding the specific inhibitor of iNOS into the coculture system significantly reversed the inhibitory effect of hUC-MSCs on Tfh cell generation. Interestingly, the efficacy of hUC-MSCs in inhibiting Tfh cells was impaired in the Transwell system, with the reduction of iNOS in both mRNA and protein levels. Taken together, our findings suggest that hUC-MSCs could effectively inhibit Tfh cell expansion through the activation of iNOS in lupus-prone B6.lpr mice, which is highly dependent on cell-to-cell contacts.

MicroRNA-663 induces immune dysregulation by inhibiting TGF-β1 production in bone marrow-derived mesenchymal stem cells in patients with systemic lupus erythematosus

Mesenchymal stem cells (MSCs) are critical for immune regulation. Although several microRNAs (miRNAs) have been shown to participate in autoimmune pathogenesis by affecting lymphocyte development and function, the roles of miRNAs in MSC dysfunction in autoimmune diseases remain unclear. Here, we show that patients with systemic lupus erythematosus (SLE) display a unique miRNA signature in bone marrow-derived MSCs (BMSCs) compared with normal controls, among which miR-663 is closely associated with SLE disease activity. MiR-663 inhibits the proliferation and migration of BMSCs and impairs BMSC-mediated downregulation of follicular T helper (Tfh) cells and upregulation of regulatory T (Treg) cells by targeting transforming growth factor β1 (TGF-β1). MiR-663 overexpression weakens the therapeutic effect of BMSCs, while miR-663 inhibition improves the remission of lupus disease in MRL/lpr mice. Thus, miR-663 is a key mediator of SLE BMSC regulation and may serve as a new therapeutic target for the treatment of lupus.Mesenchymal stem cells (MSCs) are critical for immune regulation. Although several microRNAs (miRNAs) have been shown to participate in autoimmune pathogenesis by affecting lymphocyte development and function, the roles of miRNAs in MSC dysfunction in autoimmune diseases remain unclear. Here, we show that patients with systemic lupus erythematosus (SLE) display a unique miRNA signature in bone marrow-derived MSCs (BMSCs) compared with normal controls, among which miR-663 is closely associated with SLE disease activity. MiR-663 inhibits the proliferation and migration of BMSCs and impairs BMSC-mediated downregulation of follicular T helper (Tfh) cells and upregulation of regulatory T (Treg) cells by targeting transforming growth factor β1 (TGF-β1). MiR-663 overexpression weakens the therapeutic effect of BMSCs, while miR-663 inhibition improves the remission of lupus disease in MRL/lpr mice. Thus, miR-663 is a key mediator of SLE BMSC regulation and may serve as a new therapeutic target for the treatment of lupus.

Liver damage in primary biliary cirrhosis and accompanied by primary Sjögren's syndrome: a retrospective pilot study.

Introduction Primary biliary cirrhosis (PBC) and primary Sjögrens syndrome (pSS) have been referred to as “generalized autoimmune epithelitis”. Indeed, the pathogenic mechanisms, clinical features, and optimal therapeutic approaches for them are not yet fully defined. Material and methods A retrospective analysis was carried out on clinical data obtained from 302 inpatients newly diagnosed with PBC, pSS, or the coexistence of PBC and SS between May 2011 and December 2014. Forty-two patients with abnormal hepatic function were divided into the PBC group (n = 17), the coexistent group (PBC accompanied by SS, n = 13), and the pSS group (n = 12). Their clinical symptoms, laboratory data, and pathological features were collected and analyzed when they were first diagnosed. The clinical and laboratory data were collected at 0, 1, and 3 months after treatment. Results Of the 42 patients with abnormal liver function, 4 were male and 38 were female patients. Compared with the patients in the PBC group, the patients in the other 2 groups were more likely to have an elevated erythrocyte sedimentation rate (ESR) and serum immunoglobulin G (IgG) levels. Abnormal serum immunoglobulin M levels (IgM) were more frequent in the PBC group. Corticosteroids were effective in normalizing elevated liver enzyme levels in patients with SS and in those with coexistent conditions. Conclusions This pilot study suggests that patients with PBC, pSS, and PBC/SS coexistence and having liver function abnormality share similar symptoms, but have different pathogenesis and prognosis.

THU0380 Increased Expression of Bruton Tyrosine Kinase in Patients with Lupus Nephritis and its Clinic Significance

Background Systemic lupus erythematosus (SLE) is an autoimmune disease manifested by multiorgan impairment including glomerulonephritis, cutaneous lesions and arthritis. B cells participate in the onset of SLE. As a downstream signaling molecule of B-cell receptor (BCR) signaling pathway, Bruton tyrosine kinase (Btk) is involved in the development, activation and survival of B cells. It is reported that transgenic mice overexpressing Btk specifically in B cells could produce antinuclear antibody and develop a lupus-like symptoms. Objectives The aim of our study was to identify the specific role of Btk in lupus nephritis. Methods The percentages of Btk positive CD19+ B cells from 28 SLE patients and 28 healthy donors were examined by flow cytometry. The correlation between the percentages of Btk positive CD19+ B cells and some lupus related clinical indicators were analyzed. Immunohistochemistry was used to detect the Btk expression in kidney biopsies from 8 lupus nephritis (LN) patients and 8 controls. The levels of Btk expression in glomerulus were detected by image-pro plus analysis, and represented by mean optical density (MOD). Results The frequency of Btk+CD19+ B cells from SLE patients is up-regulated compared with the healthy controls (3.89±0.31 vs 2.61±0.21, p<0.01), significantly correlating with the SLE activity (SLEDAI) (r=0.53), levels of serum anti-dsDNA antibody (r=0.41), levels of serum C3 (r=-0.41), and the amount of 24 hours urine protein (r=0.59). We also found that the frequency of Btk+CD19+ B cells in the patients with lupus nephritis was significantly higher compared with the patients without lupus nephritis (4.71±0.481 vs 3.19±0.30, p<0.05). The levels of Btk expression in glomerulus were markedly increased in LN patients compared with controls (0.04±0.01 vs 0.01±0.00, p<0.001). Conclusions Btk expression is significantly increased in LN, which may be a promising therapeutic target for the molecular therapy of SLE. Disclosure of Interest None declared

Mesenchymal Stem Cells Promote the Osteogenesis in Collagen-Induced Arthritic Mice through the Inhibition of TNF-α

Objective To investigate the effects of umbilical cord mesenchymal stem cell (UC-MSC) transplantation on joint damage and osteoporosis in collagen-induced arthritis (CIA) mice and to explore the mechanisms by which UC-MSCs modulate the osteogenic differentiation. Methods CIA mice were divided into the following treated groups: UC-MSC transplantation group, antitumor necrosis factor- (TNF-) α group, and zoledronic acid (ZA) group. Microcomputed tomography (micro-CT) was used to analyze the bone morphology parameters. Osteogenic differentiation of treated CIA mice was determined. Bone marrow mesenchymal stem cells (BM-MSCs) from CIA mice were treated with TNF-α in vitro to explore their effects on osteogenesis. Results The arthritis score was significantly reduced in the UC-MSC transplantation and anti-TNF-α-treated CIA groups, compared with control mice (P < 0.001). Micro-CT showed that CIA mice developed osteoporosis at 12 weeks after immunization. The bone morphology parameters were partially improved in UC-MSC-treated CIA mice. Impaired osteogenic differentiation functions were indicated by decreased ALP activity (P < 0.001) and reduced mRNA and protein levels of osteogenic marker genes (P < 0.05) in CIA mice compared with DBA/1 mice. UC-MSC treatment significantly upregulated the impaired osteogenic differentiation ability in CIA mice. Meanwhile, the serum TNF-α level was decreased significantly in the UC-MSC group. The osteogenesis was reduced with the addition of TNF-α in vitro. Conclusion This study demonstrated that UC-MSC transplantation not only significantly improved the joint damage but also played a beneficial role in osteoporosis in CIA mice. Mechanistically, the improved osteogenic differentiation of CIA under UC-MSC treatment may be achieved by inhibition of TNF-α.

Mesenchymal stem cells prevent podocyte injury in lupus-prone B6.MRL-Faslpr mice via polarizing macrophage into an anti-inflammatory phenotype.

BACKGROUND Podocyte injury plays a pathogenic role in the development of lupus nephritis (LN). Mesenchymal stem cells (MSCs) have shown promising therapeutic potential for LN. However, whether MSCs can prevent podocyte injury in LN remains unknown. METHODS Human umbilical cord-derived MSCs (UC-MSCs) were infused into lupus-prone B6.MRL-Faslpr (B6.lpr) mice to investigate the influences of UC-MSCs on podocyte injury in LN. Podocytes and macrophages were co-cultured with UC-MSCs in vitro to study the mechanism by which UC-MSC protect podocytes. We further explored the effects of UC-MSCs on macrophage polarization. RESULTS We found that UC-MSCs promoted the expression of podocyte-specific markers, podocin and synaptopodin, in lupus-prone B6.lpr mice, along with the improvement of lupus renal pathology in terms of reduced IgG and C3 deposition in glomeruli and decreased anti-dsDNA antibody level. Besides, UC-MSC treatment decreased podocyte foot process effacement, as UC-MSCs-treated macrophages led to less podocyte injury in vitro. Interestingly, we further found that UC-MSCs-treated macrophages exhibited an anti-inflammatory phenotype with higher expression of CD206, and lower expression of tumor necrosis factor-α and interleukin-1β. Additionally, UC-MSCs-treated lupus mice showed reduced renal macrophage infiltration and elevated CD206 expression in kidney. CONCLUSIONS Our results demonstrated that UC-MSCs ameliorated LN by preventing podocyte injury possibly through reducing macrophage infiltration and polarizing macrophage into an anti-inflammatory phenotype.

Citrullinated fibrinogen impairs immunomodulatory function of bone marrow mesenchymal stem cells by triggering toll-like receptor

Bone marrow mesenchymal stem cells (BMSC) have been shown to possess immunomodulatory activities, while its role in rheumatoid arthritis (RA) remains unknown. Citrullinated fibrinogen (cfb) has been considered as a specific autoantigen in RA pathogenesis. Our study aims to determine the role of cfb on immunomodulatory function of BMSC. We demonstrated the specific role of toll-like receptor 4 (TLR4)-NFκB pathway in the pro-inflammatory response of BMSC to cfb with increased production of interleukin (IL)-6, IL-8 and chemokine CC motif ligand 2 (CCL2). Moreover, cfb impaired BMSC-mediated suppression of peripheral blood mononuclear cells (PBMC) proliferation and reduced the production of the key immunomodulatory molecule indoleamine 2,3-dioxygenase (IDO) in BMSC. We have uncovered a previously unrecognized role of cfb in interfering BMSC-mediated immunoregulation in RA. Cfb could act as a damage-associated molecule pattern (DAMP) for BMSC and thereby contribute to the propagation of inflammation in RA.

Mesenchymal stem cells enhance autophagy of human intrahepatic biliary epithelial cells in vitro: Mesenchymal stem cells enhance autophagy

Dysfunctional autophagy in intrahepatic biliary epithelial cells (IBECs) is the main mechanism underlying the pathogenesis of bile duct lesions in primary biliary cholangitis. Autophagy may be a key pathogenesis for aetiology of primary biliary cholangitis. Immunoblotting and immunofluorescence analyses were used for the evaluation of autophagy in human intrahepatic biliary epithelial cells (HiBECs) at various time points. Glycochenodeoxycholate (GCDC) induced autophagy in HiBECs; the ratio of microtubule‐associated protein light chain 3‐II/microtubule‐associated protein light chain 3‐I (LC3‐II/LC3‐I) expression markedly increased at 48 hours, and then declined. However, compared with cells treated with GCDC alone, the expression of LC3‐II increased and the clearance of autophagosome enhanced in GCDC‐treated cells cocultured with mesenchymal stem cells (MSCs). Furthermore, the level of phosphorylation of signal transducer and activator of transcription 3 (pSTAT3) decreased in HiBECs cocultured with MSCs relative to those cultured without MSCs. Following STAT3 silencing, decreased expression of phosphorylated eukaryotic initiation factor 2α was consistently observed. The present data suggest that mesenchymal stem cells may enhance autophagic flux of HiBECs through the inhibition of STAT3 activity.